Hard disks with > 1024 Cylindars

[Art Neilson]

In article <1990Aug31.022148.5775 at gpu.utcs.utoronto.ca> utgpu!rom!mark, utgpu!rompub writes:
>I have purchased a Wren VI Harddisk for installation under SCO Xenix
>and/or SCO Unix ODT.  The disk has 1747 cylindars, 7 head and 54
>sectors/track.  I am using an Everex ESDI controller that understands
>what this disk is all about and has routines to handle it.
>
>The SCO ODT documentation suggests that such a disk is compatible as
>long as the root partition doesn't cross over the 1024 cylindar
>boundary.  Now, my limited understanding of disk geometry tells me
>that is not an easy task.  
>
>Has anyone had any experience with this or similar drives under Xenix
>or Unix.  Can it be used reliably?

You can either split your system into separate filesystems such that
root doesn't cross the boundary, or turn on sector mapping in your 
controller.  You can do this from DOS by going into debug and giving
the command g=c800:5, note that some controllers may have their ROM
at a different location, consult your controller docs.  You should
get some kinda menu with a choice for setting special options, one
of the options should enable the controller to map the sectors such
that it presents < 1024 cylinders to your OS.
-- 
Arthur W. Neilson III		| ARPA: art at pilikia.pegasus.com
Bank of Hawaii Tech Support	| UUCP: uunet!ucsd!nosc!pegasus!pilikia!art